added grouping_refresh_token handler to granthandlers

Conflicts:

	lib/OAuth/Lite2/Client/ClientCredentials.pm
	lib/OAuth/Lite2/Client/UsernameAndPassword.pm
	t/00_compile.t
updated spec

Conflicts:

	t/00_compile.t
remove unsed method
Used authorization_basic method to generate basic authorization header
added support for 'server_state' grant_type

Conflicts:

	t/00_compile.t
added import methods
added empty line
updated meta files